1. Field of the Invention
The invention relates to an electronic circuit for detecting the position, presence or velocity of an object and more specifically to such a circuit employing a phase shift of one of two signals in response to movement of the object.
2. Description of the Prior Art
The invention system has many uses, one of which is a throttle position detector. Many throttle position systems have been devised. One prior art system employs a rheostat; however, this system is subject to wear, since a wiper must be moved over a resistive material, and is subject to erroneous signals due to power supply voltage changes and resistance changes at the contact of the wiper. Another prior art system, which is contactless, employs the concept of moving one plate of a capacitor relative to the other and senses the change in magnitude of a cyclic signal in a circuit incorporating the capacitor; however, this system is vulnerable to spurious signals, power supply voltage changes, and to temperature changes. The system also finds use as an accurate and inexpensive velocity or speed detector.